1. Field of the Invention
The present invention relates to a recording medium suitable for forming a print (printed matter) having texture or image quality comparable to that of a silver halide photograph by applying liquid droplets of ink to a recording medium with an ink-jet recording process or the like; and an image forming method using the medium.
2. Related Background Art
In an ink-jet recording process, images or characters are recorded by ejecting minute droplets of a recording liquid such as ink based on various operation principles, then making them adhere to a recording medium such as paper. This process is characterized by quiet operation at high speed, facilitation of multi-color printing, high adaptability of a recording pattern and no need for development. The ink-jet recording process has become popular rapidly, because its application to an output part of an information apparatus such as copying machines, word processors, facsimiles or plotters, as well as to a printer itself, is proceeding. In recent years, digital cameras, digital videos, scanners or the like of high performance have been provided at a low cost. Owing to such circumstance, together with the spread of personal computers, printers employing an ink-jet recording system for outputting an image information obtained by such apparatuses has come to be used preferably. Under such situations, there is a demand for easy output of an image, which is comparable to a sllver-salt photograph or multi-color print using plates, through an ink-jet recording system.
In order to satisfy such demand, improvements in the structure of a printer itself or printing system, such as increase of the recording speed, heightening of resolution and full coloration, have been conducted; in addition, improvements in the structure or properties of a recording medium are under brisk investigation.
As for a recording medium used for ink-jet recording, a variety of forms have been proposed. For example, disclosed in Japanese Patent Application Laid Open No. 52-9074 is a recording medium which comprises, as an ink-receiving layer, a void-containing layer composed mainly of a silica pigment having a large specific surface area, whereby an improvement in the ink absorbing speed is intended; and in Japanese Patent Publication No. 63-22997 disclosed is a recording medium obtained by adjusting the void of a pigment layer constituting an ink-receiving layer. In Japanese Patent Application Laid-Open Nos. 55-51583 and 56-157, described is a recording medium comprising amorphous silica powder, said amorphous silica powder being added in order to heighten ink absorptivity of an ink-receiving layer, thereby providing a print dot having a high print density and free of ink bleeding.
As for a material used for the ink-receiving layer of a recording medium, an alumina hydrate has recently drawn attentions. Disclosed in U.S. Pat. Nos. 4879166 and 5104730, and Japanese Patent Application Laid-Open Nos. 2-276670, 4-37576 and 5-32037 is a recording medium comprising, as an ink-receiving layer, a layer containing an alumina hydrate of a pseudo-boehmite structure, while disclosed in Japanese Patent Application Laid-Open No. 10-94754 is a recording medium comprising an ink-receiving layer having alumina hydrate particles incorporated therein. In Japanese Patent Application Laid-Open No. 6-79967, a recording medium obtained by casting an alumina-hydrate-containing layer is disclosed as a measure for attaining both high ink absorptivity and high glossiness.
In Japanese Patent Application Laid-Open No. 11-1060, disclosed is a recording medium obtained by successively disposing a porous layer containing barium sulfate and then a layer containing an orientation-free alumina hydrate on a base material. This recording medium has an increased ink absorption rate so that generation of beading can be prevented and at the same time, has excellent print quality.
As for a manufacturing process of a recording medium by using a pigment having ink absorptivity as described above, disclosed in Japanese Patent Application Laid-Open No. 6-79967 is a process of applying a pigment-containing layer onto a fibrous base material which has high absorptivity, low smoothness and low denseness by casting, so that ink absorptivity is increased to carry out recording of an image at a high resolution in a short time. An ink-jet recording medium obtained by the above-described process, however, inevitably swells because the printed portion of the base material absorbs ink. As a result, the surface smoothness of the recording medium and the glossiness obtained by casting decrease.
There are attempts to heighten ink absorptivity by using a pigment having a large pore volume to form a structure having a large number of voids for absorbing and retaining ink, or using an ink-absorptive high-molecular material. In many cases, however, cloudiness caused by irregular reflection occurs inside of the ink-receiving layer, so that a desired image density or glossiness is not attained. Thus, the above-described attempts tend to fail in obtaining texture, image density, saturation or glossiness comparable to that of a silver halide photograph. In addition, it is the present situation that in many cases, a layer for ink absorption (ink-receiving layer) must be formed thick for attaining sufficient image density or saturation, which necessarily increases the cost of each of the material and the manufacturing process.
An object of the present invention is to provide a recording medium which is suitable for use in an image forming process employing a recording process, such as ink-jet recording process, in which recording is carried out by applying a recording liquid to a recording medium and which makes it possible to produce a print (printed matter) having texture or image quality comparable to that of a silver-salt photograph; a manufacturing process thereof; and an image forming method using the recording medium.
The recording medium of the present invention which can attain the above-described object is a recording medium comprising, on a base material an ink-receiving layer containing an alumina hydrate, wherein said ink-receiving layer is formed by applying a coating liquid containing said alumina hydrate to said base material followed by drying to form a layer to be said ink-receiving layer, swelling said layer to be said ink-receiving layer again, and pressing the swollen layer to a heated mirror-finish drum for drying; and glossiness of the surface of the recording medium on the side of the ink-receiving layer as measured at an angle of 20xc2x0 is 20% or more.
The manufacturing process of a recording medium according to the present invention comprises the steps of applying a coating liquid containing an alumina hydrate to a base material followed by drying to form a layer to be an ink-receiving layer, swelling said layer to be said ink-receiving layer again, and pressing the swollen layer to a heated mirror-finish drum for drying to form said ink-receiving layer so that the 20xc2x0 glossiness of the surface of said recording medium on the side of said ink-receiving layer is adjusted to 20% or more.
The image forming method according to the present invention comprises applying ink to the ink-receiving layer of the above-described recording medium, thereby forming an image.
The present invention makes it possible to form an image having texture and image quality comparable to those of a silver halide photograph, because a markedly high glossiness as high as 20% or more as measured at an angle of 20xc2x0 can be imparted to the surface of a recording medium on which an image is to be formed. Moreover, the present invention makes it possible to provide, easily and at a high speed, a print image which has high resolution and good quality, and at the same time has texture and image quality comparable or superior to those of a silver halide photograph, when a digital camera or the like is selected as an input system and an ink-jet recording system is employed as an output system.